Processes for breaking petroleum emulsions



J1me 1951 M. DE GROOTE EI'AL 2,558,512

PROCESSES FOR BREAKING PETROLEUM EMULSIONS Filed Nov. 1, 1949 M 7V\ M/WAMN\ MW;

CYCLOHEXANOL,

I'OOZ INVENTORS MELVIN DE GROOTE ARTHUR FWIRTEL.

OWEN H. PETT/ GILL 242 @M A TTORNEY Patented June 26, 1951 PROCESSES FORBREAKING PETROLEUM EMULSIONS Melvin de Groote, University City, andArthur F. Wirtel and Owen H. Pettingill, Kirkwood,

Mo., assignors to Petrolite Corporation, Ltd., Wilmington, DeL, acorporation of Delaware Application November 1, 1949, Serial No. 124,815

This invention relates to processes or procedures particularly adaptedfor preventing, breaking or resolving emulsions of the water-inoil type,and particularly petroleum emulsions.

Complementary to the above aspect of the invention herein disclosed isour companion invention concerned with the new chemical products orcompounds used as the demulsifying agents in said aforementionedprocesses or procedures, as well as the application of such chemicalcompounds, products, or the like, in various other arts and industries,along with the method for manufacturing said new chemical products orcompounds which are of outstanding value in demulsification. See ourco-pending application, Serial No; 124,816, filed November 1, 1949.

Our invention provides an economical and rapid process for resolvingpetroleum emulsions of the water-in-oil type, that are commonly referredto as cut oil, roily oil, emulsified oil, etc., and which comprise finedroplets of naturally-occurring waters or brines dispersed in a more orless permanent state throughout the oil which constitutes the continuousphase of the emulsion.

It also provides an economical and rapid process for separatingemulsions. which have been prepared under controlled conditions frommineral oil, such as crude oil and relatively soft waters or weakbrines. Controlled emulsification and subsequent demulsification, underthe conditions just mentioned, are of significant value in removingimpurities, particularly inorganic salts, from pipeline oil.

Demulsification, as contemplated in the pres ent application, includesthe preventive step of commingling the demulsifier with the aqueouscomponent which would or might subsequently become either phase of theemulsion in the absence of such precautionary measure. Similarly, suchdemulsifier may be mixed with the hydrocarbon component.

Briefly stated, the present process is concerned with the breaking ofpetroleum emulsions by means of certain glycol ethers ofpara-cyclohexylcyclohexanolfand particularly in the form of cogenericmixtures, as hereinafter described. These products are obtained bytreatment of para-cyclohexylcyclohexanol with ethylene oxide andpropylene oxide within the limits and manner hereinafter specified.

It is well known that a variety of compounds containing a reactivehydrogen atom, i. e., a hydrogen atom attached to oxygen, nitrogen, or

7 Claims. (Cl. 252-331) sulphur, will react with alkylene oxides,particularly ethylene oxide or propylene oxide, to yield thecorresponding glycol or polyglycol derivative. Such oxyalkylatedderivatives are readily prepared from chemical compounds in which thehydrogen atom is directly attached to oxygen,

and particularly in the case of alcohols or phenols such as aliphaticalcohols, phenols, alkylaryl alcohols, alicyclic alcohols,phenoxyalkanols, substituted phenoxyalkanols, etc. Generally speaking,it has been found advantageous to react a water-insoluble hydroxylatedmaterial, having 8 carbon atoms or more, with an alkylene oxide so as tointroduce water solubility, or, at least, significant or distincthydrophile character, with the result that the derivative so obtainedhas surface-active properties.

Examples of suitable reactants of this type include octyl alcohol, decylalcohol, dodecyl alcohol, tetradecyl alcohol, octadecyl alcohol,butylphenol, propylphenol, propylcrescl, hexylphenol, octylphenol,nonylphenol, and cardanol, as well as the corresponding alicy-clicalcohols obtained by the hydrogenation of the aforementioned phenols. Ithas'been suggested that at least some of such materials be used in theresolution of petroleum emulsions. As far as we are aware, none ofsuch-materials represents products which are acceptable indemulsification today from a competitive standpoint. In the majority ofcases, such products are apt to be one-sixth, one-fifth, one-fourth, orone-third as good as available demulsifying agents on the samepercentage-of-active material basis, or same cost basis.

We have discovered a very few exceptions to the above general situation.For example, we have discovered, if one treatspara-cyclohexylcyclohexanol with ethylene oxide and propylene oxide soas to yield a cogeneric mixture of glycol ethers, that such mixedderivative has unusual properties, provided the composition lies withina certain range, as hereinafter specified. A specific exemplification ofthis range is the product obtained by treating one mole ofpara-cyclotradictory. It is the intention at the moment only to pointout that there is no inconsistency in such description, and that,subsequently, there will be a complete explanation of why suchdesignation is entirely proper.

Para-cyclohexylcyclohexanol is obtained by the hydrogenation ofphenylphenol. The procedure is essentially the same as is employed inthe conversion of phenol to cyclohexanol. The molecular weight is 182.

The cogeneric mixtures of glycol ethers of.

para-cyclohexylcyclohexanol are usually effective demulsifying agents ona comparatively small number of oil field emulsions, which; oddlyenough, appear rather widely distributed geographically. Thesepara-cyclohexylcyclohexanol mixtures do not appear to be universallycompetitive, and, as a matter of fact, appear to be highly selective inregard to their action as demulsifying agents. However, such productshave significant utility in a number of different oil fields where theyserve better than any otheravailable demulsifying agent. Their utilitymay, of course, increase as time goes along.

It is very peculiar that the efiectiveness of the demulsifying agentsherein described seem to be limited to a very narrow range or area asfar as composition goes.

The invention will be described by reference to the accompanying drawingwhich illustrates, in conventional graphical form, compositions used inaccordance with the invention in terms of the three components. Thefigure is-the con ventional triangular graph showing compositions interms of the three components. Thus, the drawing illustrates glycolethers of para-cyclohexylcyclohexanol, or cogeneric mixtures thereof,derivable from para-cyslohexylcyclohexanol and ethylene oxide alone, orpara-cyclohexylcyclohexanol and propylene oxide alone,orparacyclohexylcyclohexanol and both propylene oxide and ethyleneoxide, in terms of the initial reagents. We have found that effectivedemusifying agents lie approximately within a small and hithertounsuspected area indicated by the trapezoid of said graph, determined bythe points 8; 9; l and II. More specifically, particularly effectivedemulsifying agents appear within a smaller range, as set forthapproximately by the area indicated by the segment of a circle in said"graph, in which the area of the segment is limited to derivatives inwhich para-cyclohexylcyclohexanol contributes at least 4% by weight ofthe ultimate compound or cogeneric mixture.

The circle itself is identified by the fact that the points i, 3 and 6appear on the circle. The more effective of these better compounds orcogeneric mixtures are those which appear within the triangle whichrepresents part of the circle and part of the segment, to wit, thetriangle identified by the points I, 3 and 6. The most effectivecompounds or cogeneric mixtures of all are those which fall within theinner central triang of the larger outer triangle identified by thepoint". i, 3 and 6, to wit, the smaller triangle identified by thepoints 2, 4 and 5. The most outstanding of these effective compounds orcogeneric mix tures is one which appears to fall substantially at thecenter of the smaller triangle, identified by point 'i. This particularpoint is obtained by treating one mole of para-cyclohexylcyclohexano".with 18 moles of propylene oxide, followed treatment with 21 moles ofethylene oxide.

In spite of the unique character of the compounds or cogeneric mixturespreviously de scribed we have made additionally an invention within aninvention. This can be illustrated by reference to the compounds orcogeneric mixture whose composition is determined by the inner triangle2, 4, 5. This preferred class of derivatives, or, for that matter, allthe hereindescribed products, can be made in three'differentways: (a) byadding propylene oxide first and then ethylene oxide; (b) by addingethylene oxide first and thenpropylene oxide; or (c) by adding the twooxides of random, indifferent, or uncontrolled addition so as to producea polyglycol ether in which the propylene radicals and ethylene radicalsdo not appear in continuous succession but are heterogeneouslydistributed.

We have found that if propylene oxide is added first and then ethyleneoxide is added, the compounds or cogeneric mixtures so obtained areinvariably and inevitably more effective as demulsifiers, and are alsomore effective for other purposes than the comparable glycol ethers ofpara-cyclohexylcyclohexanol made by combining the three reactants in anyother sequence; This will'be explained further with additionalillustrations subsequently.

As an illustration of the preparation of 'various compounds or cogenericmixtures, and particularly the most desirable ones, and also those.

which are helpful in setting the limits in the graph previously referredto, the following examples are included. In connection withtheseexamples it will be noted that the oxyalkylation ofpara-cyclohexylcyclohexanol, that is, by treatment with ethylene oxideor propylene oxide, or mixture of the two, is conventional. Theprocedure is conducted in the same manner employed in connection withother alcohols or the like, and generallyan alkaline catalyst, isemployed.

Example 1 The reaction vessel employed was a stainless.

steel autoclave with the usual devices for heating.

heat control, stirrer, inlet, outlet, etc., .Whichis conventional inthis type of apparatus. The capacity was approximately 40 gallons.The-stirrer operated at a speed. of approximately 250 R. P. M.

There were charged into the autoclave. 18.2

pounds of para-cyclohexylcyclohexanol. There were then added 12 ounces(approximately.5% by weight) of ground caustic soda. The autor clave wassealed, swept with nitrogen gas, andstirring started immediately andheat applied,

and the temperature allowed to rise to approximately C. At this pointaddition of propylene oxide was started. It was added continuously atsuch speed that it-wasabsorbed by the reaction as rapidly as added; Theamount of propylene oxide added was 104 pounds. The

time required to add this propylene oxide was slightly in excessof onehour, about 1% hours.- During this-time the temperature was maintainedat 150 to C'., using cooling water through the inner coils whennecessary, and otherwise, applying heat, if required. At the end of theaddition of the propylene oxide there was added ethylene oxide, aspreviously indicated. Th: amount of ethylene oxide added was92.4-pounds' The temperature employed, and operating con ditions, werethe same as with the addition of" propylene oxide. It is to be noted,however, that ethylene oxide appears to be more reactive and thereaction seems-to require a greater amount of cooling water to holdthe'temperature range indicated. The time required to addv the ethyleneoxide was about the same, or slightly less, usually just a little morethan an hour.

During the addition of the oxides the pressure 6 oxide employed was208.0 grams, and the amount of ethylene oxide employed was 184.8 grams.The amount of caustic soda used as a catalyst was was held atapproximately 50 pounds per square; 2.33 grams. The operating conditionswere subinch gauge pressure, or less. When all the oxide 5 stantiallythe same as on a larger scale. Actually, had been added (ethylene oxidebeing the final the reaction seemed to go faster in the small additionin this particular instance) the autoautoclave and the time ofabsorption could be clave wer permitted to stay at the sametemperreduced, if desired. In many instances absorpature range foranother half hour, even longer, tion would take place in the laboratoryautoclave if required, or until the gauge pressure had been 10 in afraction of the time required in the larger reduced to zero, orsubstantially zero, indicating autoclave; in fact, in many instancesabsorption the reaction was complete. The final product was complete in5 to 10 or minutes, as comwas an oily material, somewhat viscous innapared to one hour on a larger scale. Needless ture, resembling castoroil and havingan odor to say, on a large scale, addition must beconsuggestive of para-cyclohexylcyclohexanol. It 15 ducted carefully,because there is an obvious was soluble in water and also soluble in nonhazard in handling a large quantity of material aqueous solvents, suchas aromatic hydrocar in an autoclave, which is not necessarily presentbons, and others, although not soluble in some in the use of a smallvessel. non-polar hydrocarbon solvents. The final yield wassubstantially the total weight ofthe initial Examp 5 reactants- The sameprocedure was followed as in Ex- Emmple 2 ample 4, preceding, in everyrespect, except the The same procedure was followed as in EX- variationdescribed in Example pr 1- 4; ample 1, preceding, except that the orderof addithe ethylene OXide, Was added first and the p y tion of theoxides Was reversed, the ethylene e118 OXlde added last oxide beingadded first and the propylene oxide last. The time period, temperaturerange, pres- Example 6 u e, 4 Were p the Same as 111 a pl 1, The sameprocedure was followed as in Example p c m 4, in every instance, exceptthe modification pre Example 3 viously described in Example 3, to wit,the propyl- The same procedure was followed as in Example ene OXlde andthe Pthylene were Puxed 1, except that a mixture, to wit, 196.4 pound oftogether and added in approxlmately l5 nunutes propylene oxide andethylene oxide, were added t0 -ha f h0ur. In all other resp q over atwmhour period This mixture of ethy1 cedure was identical with thatdescribed in Exene oxide and propylene oxide was obtained from ample 104pounds of propylene oxide and 92.4 pounds of The fonOWmg table lPcludesa er1es of ethylene oxide. In this instance again the time pounds or99591119119 mlxtures Whlcl} hafve been range, temperature, and pressure,were kept th selected as exemplifying the herein included same as inExample 1, preceding products. Types of the herein noted compounds 40 orcogeneric mixtures have been produced in three Example 4 different ways:(a) first adding propylene oxide The same procedure as in Example 1,precedand h ylene oxi (11') r adding e hy ing, was conducted on alaboratory scale employf OXlde a then propylene O Mi and (C) m 1X- ing asmall autoclave having a capacity of ap- Ar mg the ethylene 0 and t ppylene OXlde proximately one liter, or up to a 5-gallon size. together ad ad th l y- The amount of para-cyclohexylcyclohexanoleme ta 1Summarlzed 1n the followlng ployed was 36.4 grams, the amount ofpropylene table:

Para-Oyclohexyl-Cyclohexanol Propylene Oxide Ethylene Oxide Point on 5 9Weight Weight Weight Ex.No. C t W ht P, C t W.rht P C t y l 5121i? 1 51131 1 1183 45111 gg iri rifi l 1183i, in ggfig 14351521 f f Grams GlycolGrams Glycol Grams Glycol E5100 Ether Ether Ether er 1 Within innertriangular area. I Duplicated for covcnience. 3 Indicates limits oftrapezoidal area.

mixture.

In the preparation of the above compounds the alkaline catalyst used waseither flake caustic soda finely ground with mortar and pastle, orpowdered sodium methylene, equivalent to by weight of thepara-cyclohexylcyclohexanol which was employed.

For reasons which are pointed out hereinafter in greater detail, it issubstantially impossible to use conventional methods and obtain a singleglycol ether of the kind described. Actually, one obtains a cogenericmixture of closely related or touching homologues. These materialsinvariably have high molecular weights and cannot be separated from oneanother by any known method without decomposition. The properties ofsuch a mixture represent the contribution of the various individualmembers of the mixture.

Although one cannot draw a single formula and say that by following suchand such procedure, one can obtain 80% or 90% or 100% of such singlecompound, yet one can readily draw the formulae of a large number ofcompounds which appear in some of the mixtures described elsewhere, orcan be prepared readily as components of mixtures which are manufacturedconventionally. Such formulae, representing significant portions ofvarious mixtures are of distinct value, insofar that they themselvescharacterize the invention, i. e., describe individual components whichare typical of the members of the cogeneric In the following formulae,since ROI-I can represent para-cyclohexylcyclohexanol, R0 is the etherradical obtained from para-cyclohexylcyclohexanol by removal of thehydrogen atom attached to the oxygen atom.

If one selects any hydroxylated compound and subjects such compound tooxyalkylation, such as oxyethylation or oxypropylation, it becomesobvious that one is really producing a polymer of the alkylene oxide,except for the terminal group. This is particularly true where theamount of oxide added is comparatively large, for instance,

8 10, 20, 30, 40, or 50'units. If such a compound is subjected tooxyethylation so as to introduce 30 units of ethylene oxide, it is wellknown that one .;does not obtain asingle constituent, which, for

the sake of convenience, may be indicated as RO(C2H4O)30H. Instead, oneobtains a cogeneric mixture of closely related homologues in Which theformula may be shown as the following: RO C2H4O) 11H, wherein mas far asthe statistical average goes, is 30, but the individual members presentin significant amount may vary from instances where n has a value of 25,and perhaps less, to a point where 11. may represent-35 or more. Suchmixture is, as stated, a cogeneric closely related series of touchinghomologous compounds. Considerable investigation has been made in regardto the distribution curves for linear polymers. Attention is directed tothe article entitled Fundamental Principles of CondensationPolymerization, by Paul J. Flory, which appeared in Chemical Reviews,volume 39, No. 1, page 137.

Unfortunately, as has been pointed out by Flory and other investigators,there is no satisfactory method, based on either experimental ormathematical examination, of indicating the exact proportion of thevarious members of touching homologous series which appear in cogenericcondensation products of the kind described. This means that from thepractical standpoint, i. e., the ability to describe how to make theproduct under consideration and how to repeat such production time aftertime without difiiculty, it .is'necessary'to resort to some other methodof description.

Actually, from a practical standpoint it is much more satisfactory,perhaps, to describe the ultimate composition in terms of the reactants,i. e., para-cyclohexylcyclohexanol and the two alkylene oxides. Thereason for this statement is the following: If one selects a specificcompound, .it must be borne in mind that such compound is specific onlyinsofar that the cogeneric mixture in terms of a statistical averagewill conform to this formula. This may be illustrated by an example suchas RO(C3HsO)1s(C2I-L1-O)21H. If one combines the reactants in thepredetermined weight ratio so as togive theoretically this specificcomponent, and assuming that only one chemical compound were formed,what happens is that, although this particular compound may be presentin a significant amount and probably less than 50%, actually one obtainsa cogeneric mixture of touching homologues, in which the statisticalaverage does correspond to this formula. For instance, selectingreactants, which, at least theoretically, could give the single compoundRO(C3HeO)1a(C2H40)21H, what actually happens is that one obtains a sortof double cogeneric mixture, for the reason that in each batch orcontinuous addition of an alkylene oxide a cogeneric mixture is formed.Since the present products require the addition of at least twodifferent multi-molar proportions of each of two different alkyleneoxides (ethylene oxide and propylene oxide) it becomes obvious that arather complex cogeneric mixture must result.

This can be best illustrated by example. Assume that one is going to usethe indicated ratio, to wit, one pound mole ofpara-cyclohexylcyclohexanol, 18 pound moles of propylene oxide and 21pound moles of ethylene oxide. The initial step involves the treatmentof one pound mole of para-cyclohexylcyclohexanol with 18 pound moles ofpropylene oxide so as to yield theoretically RO-(C3H6O)1sH; actually, aspointed out, one does not obtain RO(C3H60)1&H, in which n is; 18, butreally one obtains a cogeneric mix- .ture, in which there are presentsignificant amounts of liomologues in which n varies from 10,11 and 12on up to 23, 24v and possibly 25 or' extent, for reasons which have beendescribed in connection with oxyethylation and which now are magnifiedto a greater degree by oxypropylation. Stated another way, it isprobable that the cogeneric mixture represents something like'RO(CsI-Is)n(C2H4O)n'I-I, in which, as previously 1' ointed out,components present in important percentages are those in which n couldvary from anywhere beginning with to 12, on up to} 20, or 24 to 26. Bythe same token, components present in important percentages are thosewhich n could vary anywhere from 13 or 14 to the higher 20s, such as 26,27, 28, or 29. Indeed, homologues of a lower or a higher value of n andn will be present in minor amounts, the

:percentage of such components decreasing, the

further removed they are from the average composition. However, in spiteof such variation in regard to the cogeneric mixture, the ultimatecomposition, based on the ingredients which enter into it and based onthe statistical average of such constituents, can still be expressed bythe formula RO(C3H60)18(C2H40) 21H. This actual product exists to somedegree in the cogeneric mixture, but it should be looked .upon as a-istatistical average formula rather than the structure of a single orpredominant compound in the mixture.

A second reason for employing a reaction mixture to describe theproduct, is the fact that the molal proportions need not represent wholenum selects We have just pointed out that if one molal proportionscorresponding to RO(C3H6O)18(C2H4O)21H, then the constituents are addedin actual'molar proportions, based on whole numbers. If, however, oneselects a point in the inner triangular area of the accompanying graph,which, when recalculated in terms of molar proportions, produces afractional numher, there is still no reason why such proportion ofinitial reactant should not be adopted. For instance, one might select apoint in the triangular graph, which, when calculated in terms ofmolecular proportions, represents a formula, such as the following:

R0 (Cal-I60) 18.5(021'140) 21H statistical value, but not in the sensethat there actually can be a compound corresponding to suchformula.Further discussion of this factor 10 appears unnecessary in light ofwhat has been said previously.

Such mixture could, of course, be treated with 21 pound moles ofethylene oxide. Actually, all that has been said sums up to this, andthat is, that the most satisfactory way, as has been said before, ofindicating actual materials obtained by the usual and conventionaloxyalkylation process is in terms of the initial reactants, and it isobvious that any particular point on the triangular graph, from apractical aspect, invariably and inevitably represents the statisticalaverage of several or possibly a dozen or more closely related cogenersof almost the same composition, but representing a series of touchinghomologues. The particular point selected represents at least thecomposition of the mixture expressed empirically in the terms of 'acompound representing the statistical average.

Previous reference has been made to the fact that comparatively fewoxyalkylated derivatives of simple hydroxylated compounds find utilityin actual demulsification practice. We have pointed out that we havefound a very few exceptions to this rule. The fact that exceptionsexist, as in the instant invention, is still exceedingly difiicult toexplain if one examines the slight constribution that the end group,derived from the hydroxylated material, makes to the entire compound.Referring for the moment to a product of the kind which has beendescribed and identified by the formula RO (CsHsO) 18(C2H40) 21H itbecomes apparent that the molecular weight is in the neighborhood of2100 and actually the para-cyclohexylcyclohexanol contributes less than10% of the molecular weight. As a matter of fact, in other comparablecompounds the paracyclohexylcyclohexanol may contribute as little as 4%or 5% and yet these particular compounds are effective demulsifiers.Under such circumstances, it would seem reasonable to expect that someother, or almost any other, cyclic fi-carbon atom compound comparable toparacyclohexylcyclohexanol would yield derivatives equally effective.Actually, this is not the case. We know of no theory or explanation tosuggest this highly specific nature or action of the compound orcogeneric mixture derived from paracyclohexylcyclohexanol.

Referring to an examination of the previous list of 32 compounds, it isto be noted that in certain examples, for instance, Examples 9 to 15,inclusive, all the propylene oxide is added first and then the ethyleneoxide is added. Compounds indicated by Examples 1 to 8 are substantiallythe same as far as composition goes, but are reversed, insofar that theethylene oxide is added first and then the propylene oxide. Othercompounds having substantially the same ultimate composition, or atleast very closely related ultimate compositions, having a furthervariation in the distribution of the propylene oxide and ethylene oxide,are exemplified by Formulae 16 to 32, inclusive.

As has been pointed out previously, for some reason which we do notunderstand and for which we have not been able to offer any satisfactorytheory, we have found that the best compounds, or more properly,cogeneric mixtures, are obtained when all the propylene oxide is addedfirst and then all the ethylene oxide is added. Although this is true toat least some extent in regard to all compositions within thetrapezoidal such cogeneric mixtures.

areain the triangular graph, yetit is particularly true if thecomposition comes within the segment of the circle of'the accompanyingdrawing. In such event, one obtains a much more effective demulsifierthan by any other combination employing ethylene oxide alone, propyleneoxide alone, or any variation in the mixture of the two, as illustratedby other formulae. In fact the compound or cogeneric mixture soobtained, as far as demulsification is concerned, is not infrequently atleast one-third better than any other derivative obtained in the mannerdescribed involving any of the other above variations.

The-significance of what has been said previously becomes more emphaticwhen one realizesthat, inessence, we have found that one isomer is amore effective demulsifying agent than another isomer. The Word isomeris not exactly right, although it is descriptive for the purposeintended, insofar that we are not concerned with a single compound, butwith a cogeneric mixture, which, in its statistical average, correspondsto r such compound. Stated another way, if we start with one pound moleof para-cyclohexylcyclohexanol, 18 pound moles of propylene oxide and 21pound moles of ethylene oxide, we can prepare two diiferent cogenericmixtures, which, on a statistical average, correspond to the following:

There is nothing we know which would suggest that the latter be a muchmore effective demulsifying agent than the former and also that it bemore effective for other industrial purposes. The

applicants have had wide experience with a wide variety ofsurface-active agents, but they are unaware of any other similarsituation, with the exception of a few instances which are thesubsubject-matter claimed in our co-pending applications Serial Nos.124,817 and 124,818, both filed November 1,-1949.

Reference has been made to the fact that the product herein specified,and particularly for use as a demulsifier, represents a cogenericmixture of closely related homologues. This does not mean that one couldnot use combinations of For instance, in the previous table data havebeengiven for prepara- -tion of cogeneric mixtures which statisticallycorrespond, respectively, to points I, 3 and 6. Such three cogenericmixtures could be combined in equal weights so as to give a combinationin which the mixed statistical average would correspond closely to point'7.

Similarly, one could do the same thing by preparing cogeneric mixturescorrespondingtto points 2, 4 and 5 described in the previous table.

'* Such mixture could then be combined in equal parts by weight to giveanother combination which would closely correspond on a mixedstatistical basis to point 1. Nothing said herein is intended topreclude such combinations of this or similar type.

We need not add that instead of subjecting para-cyclohexylcyclohexanolalone to oxyethylation and oxypropylation, or, inversely, tooxypropylation and oxyethylation, or simultaneous .treatment with bothoxides, one can employ a "mixture of cyclohexylcyclohexanol along with.some other desired .reactant such as alphaterpineol. For a number ofreasons, it is ordinarily desirable to use a procedure in which only oneproduct is reacted at a time.

Conventional demulsifying agents employed in the treatment of. oil fieldemulsions are used as such, or after dilution with any suitable solvent.such as water, petroleum hydrocarbons, such as benzene, toluene, xylene,tar acid oil, cresol, anthracene oil, .etc. Alcohols, particularlyaliphatic alcohols, such as methyl alcohol, ethyl alcohol, denaturedalcohol, propyl alcohol, butyl alcohol,'hexyl alcohol, octyl alcohol,etc., may be employed as diluents. Miscellaneous solvents, such as pineoil, carbon tetrachloride, sulfur dioxide extract obtained in therefining of petroleum, etc., may be employed as diluents. Similarly thematerial or materials employed as the 'demulsifying agent of our processmay be admixed with one'or more of the solvents customarily used inconnection with conventional demulsifying agents. Moreover, saidmaterial or materials maybe used alone or in admixture with othersuitable well-known classes of demulsifying agents.

It is well known that conventional demulsifying agents may be used in awater-soluble form, or in an oil-soluble form, orin a form exhibitingboth 011- and water-solubility. Sometimes they may be used in a formwhich exhibits relatively limited oil-solubility. However, since suchreagents are frequently used in a ratio of l to 10,000 or l to 20,000,or 1 to 30,000 or even 1 to-40,000, or 1 to 50,000, as in desaltingpractice, such an apparent insolublity in oil and water. is notsignificant because said reagents undoubtedly have solubility withinsuch concentrations. 'This same fact is true in regard to the materialor materials employed as the demulsifying agent of our process.

=In practising our process for resolving petroleum emulsions of thewater-in-oil type, a treating agent or demulsifying agent of .the kind,above described is brought into contact with or caused r to act upontheemulsion to-be treated, in'any of the various apparatus now generallyused to resolve or-break petroleum emulsions with a chemical reagent,the above procedure being used alone or in combination with otherdemulsifying procedure, such as the electrical dehydration process.

One type of procedure is to accumulate avolume of emulsified oil in atank. and conducta batch treatment type of, demulsification procedure torecover clean oil. In thisprocedure the emulsion is admixedwith thedemulsifier, for example by agitatingv the tank of, emulsion, and slowlydripping demulsifier into the emulsion. In some cases mixing is achievedby heatingthe emulsion while dripping .inthe ,dem-ulsifier, dependingupon the convection currents in the emulsion to producesatisfactoryadmixture. In a third modification of this type oftreatment, a circulating pumpwithdraws emulsion from, c. g., the bottomof the tank,land re -introduces it into the top of the tank, the,demulsifier beingadded, for example, at the suction side ofsaid'circulating pump.

In a secondtype of'treating procedureflthe demulsifier is introducedinto the well fluids at the well-head or at some point between thewellhead and the final oil storage tank, by means of an adjustableproportioning mechanism or ,pro-

.portioning pump. Ordinarily the fiow offluids through the subsequen lins nd fitt n s ufi es to produce the desired degree of mixing ofdemuisifier and emulsion, although in some instances additional'mixingdevices may be introduced into the flow system. In this generalprocedure, the system may include various mechanical devices forwithdrawing free water, separating entrained water, or accomplishingquiescent settling of the chemicalized emulsion. Heating devices maylikewise be incorporated in any of the treatingprocedures describedherein.

A third type of application (down-,the-hole) of demulsifier to emulsionis to introduce the demulsifler either periodically or continuously indiluted or undiluted form into the well and to allow it to come to thesurface with the well fluids-and then to flowthe chemicalized'emulsionthrough any desirable surface equipment, 'such as employed in the othertreating procedures. This particular type of application is decidedlyuseful-when the demulsifier is used in connection with'acidification ofcalcareous oil-bearing strata, especially if suspended in or dissolvedin the acid employed for acidification.

In all cases, it will be apparent from the foregoing description, thebroad process consists simply in introducing a relatively smallproportion of demulsifler into: a relatively large proportion ofemulsion, admixing. the chemical and emulsion either through naturalflow or through special apparatus, with or without the application ofheat, and allowing the mixture to stand quiescent until the undesirablewater content of the emulsion separates and settles from the mass.

The following is atypical installation:

A reservoir to hold the demulsifier of the kind described (dilutedorundilutedl is placed at the well-head where the efiiuent liquids leavethe well. This reservoir or' container, which may vary from gallons to50 gallons for convenience, is connected to a proportioning pump whichinjects the demulsifier drop-wiseinto the fluids leaving the well. Suchchemicalized fluids pass through the fio wline into a settling tank. Thesettling tank consists of a tank of any convenient size, for instance,one which will hold amounts of fluid produced in' i to 24 hours (500barrels to 2000 barrels capacity), and in which there is a perpendicularconduit from the top of the tank to almost the very bottom so as topermit the incoming fluids to pass from the top of the settling tank tothe bottom, so that such incoming fluids do not disturb Stratificationwhich takes place during the course of demulsification. The settlingtank has two outlets, one being below the water level to drain ofi thewater resulting from demulsification or accompanying the emulsion asfree water, the other being an oil outlet at the top to permit thepassage of dehydrated oil to a second tank, being a storage tank, whichholds pipeline or dehydrated oil. If desired, the conduit or pipe whichserves to carry the fluids from the well to the settling tank mayinclude a section of pipe with baflies to serve as a mixer, to insurethorough distribution of the demulsifier throughout the fluids, or aheater for raising the temperature of the fluids to some convenienttemperature, for instance, 120 to 160 F., or both heater and mixer.

Demulsification procedure is started by simply setting the pump so as tofeed a comparatively large ratio of demulsifier, for instance, 1:5,000.

As soon as a complete break or satisfactory demulsification is obtained,the pump is regulated until experience shows that the amount ofdemulsifier being added is just suflicient to produce '14 clean ordehydrated oil. The amount being fed at such stage is usually 1:10,000,1:l5,000, 1 :20,000, or the like.

In many instances the oxyalkylated products herein specified asdemulsifiers can be conveniently. used without dilution. However, aspreviously noted, they may be diluted as desired with any suitablesolvent. For instance, by mixing 75parts by weight of an oxyalkylatedderivative, for example, the product of Example 1, with 15 parts byweight of xylene and 10 parts by weight of isopropyl alcohol, anexcellent demulsifier is obtained. Selection of the solvent will vary,

depending upon the solubility characteristics of the oxyalkylatedproduct, and of course, will be dictated in part .by'economicconsiderations, i. e., cost. 7

As noted above, the products herein described may be used not only indiluted form, but also may be used admixed with some other chemicaldemulsifier. For example, a mixture which exemplifies such combinationis illustratedby the following:

Oxyalkylated derivative, for example, the product of Example 1, 20%;

A cyclohexylamine salt of a polypropylated naphthalenemonosulfonic'acid, 24%;

An ammonium saltof a polypropylated naphthalene mono-sulfonic acid, 24%;

A sodium salt of oil-soluble mahogany petroleum 'sulfonic acid, 12%;

A high-boiling aromatic petroleum solvent,

Isoprop'yl alcohol, 5%.

Elsewhere in the specification the word isomer has been used thus:isomerf, It is not believed there is any confusion between suchterminology in that particular instance and what is said immediatelypreceding.

Having thus described our invention, what we claim as new and desire tosecure by Letters Patent is:

l. A process for breaking petroleum emulsions of the water-in-oil type,characterized by subjecting the emulsion to the action of a demulsifierincluding at least one cogeneric mixture of a homologous series ofglycol ethers of para-cyclohexylcyclohexanol; said cogeneric mixturebeing derived exclusively from para-cyclohexylcyclohexanol, ethyleneoxide and propylene oxide in such weight proportions so the averagecomposition of said cogeneric mixture stated in terms of initialreactants lies approximately within the 15 trapezoidal area of the graphin the accompanyingdrawing defined approximately by points 8, 9, l andII.

2. A process for breaking petroleum emulsions of the water-in-oil type,characterized by subjecting the emulsion to the action of a demulsifierincluding a cogeneric mixture of a homologous series of glycol ethers ofpara-cyclohexylcyclohex'anol; said cogeneric mixture being derivedexclusively from para-cyclohexylcyclohexanol, ethylene oxide andpropylene oxide in such weight proportions so the average composition ofsaid cogeneric mixture stated in terms of initial reactants liesapproximately within the trapezoidal area of the graph in theaccompanying drawing defined approximately by points 8, 9, l0 and II.

3. A process for breaking petroleum emulsions of the water-in-oil type,characterized by subjecting the emulsion to the action of a demulsifierincluding a cogeneric mixture of a homologous s'eries of glycol ethersof para-cyclohexylcyclohexanol; said cogeneric mixture being derivedexclusively from para-cyclohexylcyclohexanol, ethylene oxide andpropylene oxide in such weight proportions so the average composition ofsaid cogeneric mixture stated in terms of initial reactants liesapproximately within the segment of the circle of the graph in theaccompanying drawing in which the minimum para-cyclohexylcyclohexanolcontent is at least 4% and which circle is identified by the fact thatpoints I, 3, and 6 lie on its circumference.

4. A process for breaking petroleum emulsions of the water-in-oil type,characterized by subjecting the emulsion t0 the action of a demulsifierincluding a cogeneric mixture of a homologous series of glycol ethers ofpara-cyclohexylcyclohexanol; said cogeneric mixture being derivedexclusively from para-cyclohexylcyclohexanol, ethylene oxide andpropylene oxide in such weight proportions so the average composition ofsaid cogeneric mixture stated in terms of initial reactants liesapproximately within the triangular area of the graph in theaccompanying drawing defined by points I, 3, and 6.

5. A process for breaking petroleum emulsions of the water-in-oil type,characterized by subjecting the emulsion to the action of a demulsifierincluding a cogeneric mixture of a homologous series of glycol ethers ofpara-cyclohexylcyclohexanol; said cogeneric mixture being derivedexclusively from para-cyclohexylcyclohex anol, ethylene oxide andpropylene oxide in such weight proportions so the average composition ofsaid cogeneric mixture stated in terms of initial reactants liesapproximately within the triangular area of the graph in theaccompanying drawing define-d by points 2, 4 and 5.

6. A process for breaking petroleum emulsions of the water-in-oil type,characterized by subjecting the emulsion to the action of a demulsifierincluding a cogeneric mixture of a homologous series of glycol ethers ofpara-cyclohexylcyclohexanol; said cogeneric mixture being derivedexclusively from para-cyclohexylcydohexanol, ethylene oxide andpropylene oxide in such weight proportions so that average compositionof said cogeneric mixture stated in terms of initial reactants liesapproximately at point I in the graph in the accompanying drawing.

7. A process for breaking petroleum emulsions of the water-in-oil type,characterized by subjecting the emulsion to the action of a demulsifierincluding a single cogeneric mixture of a homologous series of glycolethers of para-cyclohexylcyclohexanol; said cogeneric mixture beingderived exclusively from para-cyclohexylcyclohexanol, ethylene oxide andpropylene. oxide in such weight proportions so the average compositionof said cogeneric mixture stated in terms of initial reactants liesapproximately at point 7 in the graph in the accompanying drawing.

MELVIN DEGROOTE. ARTHUR F. WIRTEL. OWEN H. PETTINGILL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,130,525 Coleman et a1 Sept. 20,1938 2,176,834 Bruson Oct. 17, 1939 2,213,477 Steindorff et a1 Sept .3,1940 2,233,383 De Groote et al Feb. 25, 1941 2,243,330 De Groote-et alMay 27, 1941 2,307,058 Moeller Jan. 5, 1943 2,317,726 Boedeker et alApr. 27, 1943 2,330,474 De Groote Sept. 28, 1943 2,425,755 Roberts et alAug. 19, 1947 2,425,845 Toussaint et al Aug. 19, 1947

1. A PROCESS FOR BREAKING PETROLEUM EMULSION OF THE WATER-IN-OIL TYPE,CHARACTERIZED BY SUBJECTING THE EMULSION TO THE ACTION OF A DEMULSIFERINCLUDING AT LEAST ONE COGENERIC MIXTURE OF A HOMOLOGEOUS SERIES OFGLYCOL ETHERS OF PARA-CYCLOHEXYLCYCLOHEXANOL; SAID COGENERIC MIXTUREBEING DERIVED EXCULSIVELY FROM PARA-CYCLOHEXYLCYCLOHEXANOL, ETHYLENEOXIDE AND PROPYLENE OXIDE IN SUCH WEIGHT PROPORTIONS SO THAT THE AVERAGECOMPOSITION OF SAID COGENERIC MIXTURE STATED IN TERMS OF INITIALREACTANTS LIES APPROXIMATELY WITHIN THE TRAPEZOIDAL AREA OF THE GRAPH INTHE ACCOMPANYING DRAWING DEFINED APPROXIMATELY BY POINTS 8, 9, 10 AND11.